text:
Do commercial aeroplanes use ABS to brake?
I have read that the wheel brakes on an aeroplane are by for the most efficient means of stopping it. I was wondering whether in low grip situations, such as in rain or snow, an ABS (Anti-lock Braking System) system is used to ensure the wheels do not lock. If not, why is this not necessary?

Yes, for much longer than automobiles do.

I heard somewhere that is easier than for cars because you have direct access to ground speed thanks to some wheels that has no brake. Thus, you can adjust the brake strength to avoid having too great speed difference between braked wheels and non-braked wheels.

I can't think of any car with unbraked wheels ... excluding antiques.

Define "commercial".  A C172 in commercial operation does not have ABS brakes.

@a.out: A C-172 doesn't have enough payload capacity to carry any useful amount of passengers or freight.

Yes, they do. They are called Anti-Skid and they go from Mark I of 1948, with simply an on-off switch triggered by wheel lock, till Mark V (or at least that's the last I've seen), with quite complex control systems and sensors behind.
The full details are a bit long to include them all here (there are entire book sections about them). For a brief overview, see this presentation from slide 12 till 18.

The basic system developed for airplanes is what led to ABS in automobiles; planes had it first.

Anti-skid Mark I may date from 1948, but the idea and implementations of it date from the late 1920s.

To extend the comparison with automobiles, Anti-Skid is rather more like a modern traction control system than simply anti-lock brakes.  The braking system is actively manipulating the braking effort on all wheels to assist in vectoring the vehicle.

It is not called ABS but Anti-Skid, but the principle is similar. All large aircraft have it.
The purpose is however slightly different. In aircraft the nose wheel has relatively little weight on it and is usually not braked, so directional control, the main reason for ABS in cars, is possible¹ even without anti-skid. However due to the higher speeds and weights involved, aircraft have much higher risk of skidding and hydro-planning and when either happens, it can severely damage the tires, so the anti-skid is to prevent that.

¹ To an extent. Since the nose wheel has little weight on it, it also has limited authority, so if the braking force becomes too asymmetric, the nose wheel can't compensate for it.

aircraft have much higher risk of hydro-planning and the anti-skid is to prevent that that's secondary, the risk for aircraft is skidding even without any water: it leads to uneven usage of the tires, up to puncturing them.

Skid damage: http://www.aerospaceweb.org/question/planes/q0245a.shtml

@Phil Fascinating.  90-degree lock on the front gear, caused by an  improperly installed shock absorber.  Classic poka-yoke!

Aircraft also usually have a rudder, which tends to help with directional control.  Also, runways are generally far flatter and evener than roads.

@Federico: In the realm of possible badness of consequences, blown tires << high-speed overrun.

The ABS systems in automobiles were based on the systems that had been in use in aircraft for decades.

ABS was first developed for aircraft use in 1929 by the French automobile and aircraft pioneer Gabriel Voisin, as threshold braking on airplanes.

Source: https://en.wikipedia.org/wiki/Anti-lock_braking_system#History

The first ABS system used in a car was the Dunlop Maxaret system, which was developed for aircraft (and used in a lot of British aircraft in the 1950s and 1960s). It was used in the Jensen FF, introduced in 1966. From 1971, car manufacturers introduced purpose-built automotive ABS.


text:
What's the minimum roll rate a commercial airliner would have with maximum aileron deflection?
If the maximum aileron deflection possible was commanded on a commercial airliner, how fast would the aircraft roll?
I don't think there's many reasons to bank a large aircraft quickly, but what I want to know is whether it's even possible to roll it at rates such as 10-15 degrees per second or more.

Depends on which airliner?

The achievable roll rate depends on altitude. At sea level, big aircraft have very low roll rates, because their roll damping is very high due to the large wingspan. Roll damping goes up with the square of the wingspan, whereas the aileron moment grows linearly with wingspan.
If the aircraft flies high enough, the roll rate will go up inversely to the change in density. This is because the flight speed increases inversely with the square root of density, so the same roll rate will cause less change in the local angle of attack on the outer wing (which is the mechanism which causes roll damping). Thus, in 12 km altitude the roll rate will be twice of what it is at sea level (at the same CAS). That is why large airliners have special high-speed ailerons at midspan: They suffice for control, and using the outboard ailerons would stress the wing a lot more. Also, outboard ailerons on high aspect ratio wings cause considerable torsion, such that the wing twist from aileron deflection will reduce aileron effectiveness. Inboard ailerons are much less affected by this effect.
I would wager to say that any airliner will be perfectly capable of 15°/s roll rates if you deflect the outboard ailerons (without overstressing the wings).
The high altitude research airplane Strato 2C had a roll rate during approach of only 2°/s! This was no real problem, because the large wing (56.5 m wingspan) would not be affected by gusts when the aircraft flew lower than approx. 30 m. The turbulence is so small scale close to the ground that the gusts would average out over the large wing, and the aircraft calmed down when sinking below 30 m, even in gusty weather. At 18 km altitude, however, it handled almost like a fighter aircraft.

Well explained. Did you know that the A380 dynamically controls all individual ailerons to achieve roll control and minimize wing loading at the same time? The system is nicknamed VDS 'valse des ailerons' (waltz of the ailerons) by Airbus. The rudder does the same (VDR).

FAA part §23.157 say that

in a takeoff configuration (flaps on takeoff landing gear retracted, speed trimmed at 1.2 $V_{S1}$ or 1.1 $V_{MC}$ whichever is greater) a roll of 30° must be reversible within 5 seconds for a plane of less than 6.000 pounds up to 10 seconds for planes over 12.500 pounds

on approach (flaps in landing position, gear extended, speed trimmed at $V_{ref}$) this is reduced to 4 seconds for planes less than 6000 pounds up to 7 for planes over 12500 pounds

This is an average roll rate of 6° per second on takeoff and 8° per second on approach on large airplanes.

§23.157   Rate of roll.
(a) Takeoff. It must be possible, using a favorable combination of
controls, to roll the airplane from a steady 30-degree banked turn
through an angle of 60 degrees, so as to reverse the direction of the
turn within:
(1) For an airplane of 6,000 pounds or less maximum weight, 5 seconds
from initiation of roll; and
(2) For an airplane of over 6,000 pounds maximum weight, $\frac{W+500}{1,300}$ seconds, but not more than 10 seconds, where W is the weight in
pounds.
(b) The requirement of paragraph (a) of this section must be met when
rolling the airplane in each direction with—
(1) Flaps in the takeoff position;
(2) Landing gear retracted;
(3) For a single-engine airplane, at maximum takeoff power; and for a
multiengine airplane with the critical engine inoperative and the
propeller in the minimum drag position, and the other engines at
maximum takeoff power; and
(4) The airplane trimmed at a speed equal to the greater of $1.2 V_{S1}$ or
$1.1 V_{MC}$, or as nearly as possible in trim for straight flight.
(c) Approach. It must be possible, using a favorable combination of
controls, to roll the airplane from a steady 30-degree banked turn
through an angle of 60 degrees, so as to reverse the direction of the
turn within:
(1) For an airplane of 6,000 pounds or less maximum weight, 4 seconds
from initiation of roll; and
(2) For an airplane of over 6,000 pounds maximum weight, $\frac{W+2,800}{2,200}$ seconds, but not more than 7 seconds, where W is the weight in pounds.
(d) The requirement of paragraph (c) of this section must be met when
rolling the airplane in each direction in the following conditions—
(1) Flaps in the landing position(s);
(2) Landing gear extended;
(3) All engines operating at the power for a 3 degree approach; and
(4) The airplane trimmed at $V_{REF}$.

A320 has maximum rate of roll 25°/s (according to this Flight article). And note that since A320 is fly-by-wire with augmented controls, this is not maximum possible with full aileron deflection but what maximum sidestick deflection will command. Depending on speed full deflection may cause higher rate of roll so the limit is achievable across reasonable range of speeds.
There is one good reason to roll large aircraft quickly: to counter effect of turbulence. Turbulence can roll even big aircraft pretty quickly (strong turbulence may easily roll the aircraft to more than 45° under a second) and the pilots will want to return it to level quickly to avoid changing direction and loosing much altitude.

According to http://www.smartcockpit.com/docs/A320-Flight_Controls.pdf, 15 deg/s is the Normal Law roll rate target at max input.

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

sort: votes


text:
How can reducing power too quickly on a piston engine damage it?
In many places, it's been stated that you should reduce power slowly to prevent engine damage.  Depending on who you talk to, some say you should reduce the manifold pressure by 1 inch per minute, others say two. However, I'm not sure just how reducing power quickly will damage an engine, and if you do, what would happen. Could someone explain?

The main concern cited in regards to reducing power too quickly is that you could shock cool the engine.  A sudden decrease in power, particularly at high altitudes where it is cold can cause a rapid decrease in temperature of the engine which can cause damage to the cylinder heads.
However the theory is very controversial because there is no evidence that the cooling causes a problem, and in fact the engine cools much more quickly when you shut it down at the end of a flight.  A very good article going into more specifics about cooling of aircraft engines is here:  the physics and metallurgy of "shock cooling".
One of the more interesting points that it discusses is that only about 12% of the heat generated from combustion ends up making its way through the block and is dissipated by air cooling (cooling fins).  This means that most of the heat is already going somewhere else anyway (the largest part goes out the exhaust), and the "air cooling" doesn't make that big of a difference anyway.
As always, be sure that you follow all recommendations and limitations from your POH or engine manufacturer in regards to engine cooling, CHT's, etc. since they could have procedures for other reasons as well.

I've never put a lot of stock in the theory of shock cooling for the average GA aircraft. Just think of all the multi-engine trainers out there that regularly shut off the non-critical engine possibly dozens of times every day. How often do those engines develop problems not seen by the other?
Now, if you were flying a turbocharged engine at 25,000 feet and suddenly yanked the throttle to idle, I could see it having an effect. If you did it repeatedly, I could see it having a very bad effect.

My TIO-540 at cruise at 30" MP runs 300F CHT and 1550F turbine-inlet temperature for the turbocharger. That makes it one of the hottest running engines in GA. The POH recommends 5 minutes if cooldown before shutdown to prevent hot oil from pooling near the turbocharger.  I typically let the engine run at idle power until all the temps stabilize, which means no more heat will dissipate with the engine running, and then pull the mixture.

I also gently reduce the power in the descent down to 20" MP which at which point it's no longer running hot (relatively), and then don't worry about it. 10 minutes is a typical descent from typical cruise altitudes in the teens at 175-200kts true. You can't descend at 30" without heading to wards Vne anyway

I don't how much value the shock cooling has, but the problem is that the cylinders cool down faster than the pistons, which reduces the clearance between them and increases wear. When you shut the engine down, the pistons are not moving, so it does not matter then.

I'm generally not a fan of the shock-cooling theory myself, but I am a fan of "don't abuse your engine".
Piston engines have lots of moving parts. Abrupt power changes, whether caused by advancing the throttle or retarding it, cause all of those moving parts to change speeds faster than inertia and kindness would like.
If you want to be kind to your engine open or close the throttle at a reasonable pace during normal operations.  Reasonable varies of course - Generally 2-3 seconds from idle to full throttle seems reasonable for takeoffs (you might be a little more aggressive on power-off stall recovery, but taking 1-2 seconds to push the throttle back in shouldn't really affect your recovery).
On the other side, you should rarely have to go from full-throttle to idle, but when practicing engine-out scenarios or similar taking a second or two to smoothly reduce the power from cruise to idle rather than simply yanking on the throttle is nicer for you and your engine.

Of course all of the advice above about being nice to your engine goes out the window in a real emergency - your priority is your safety, the safety of your passengers, and the safety of people on the ground.
If you actually stall the wing, or need to abort a takeoff, or anything else happens where your first instinct is a rapid power change don't hesitate to rapidly put the throttle where you need it, and the engine can like it or lump it as long as it does what its told.

I think one has to abandon the idea of shock cooling as a single event which will cause a cylinder immediately to crack. Instead one has to think about it as cyclic thermal fatigue where material damage will be accumulated incrementally through a number of such cyclic events.
Thermal cycles are an inherent part of the normal wear & tear that any IC engine has to endure and which in the end results in a  finite TBO instead of infinite engine life.  Start up of a cold engine, shut down of a hot engine or major changes in power setting belong to a normal operation cycle.  The specified TBO of an engine implicitely contains a certain number of thermal cycles of these kinds that can be sustained without premature failure.
Turbine manufacturers who are dealing with similar life limiting problems take a more sophisticated approach and explicitely include both the number of cycles and the number of (continous duty) operating hours into their maintenance interval (=TBO) considerations. Furthermore the severity of different events is considered by applying respective weight factors. A cold start e.g. costs more engine life than a warm startand therefore has a higher weight factor.
Now the analogy to the shock cooling issue should become apparent. In general each power reduction of a hot engine after a climb under fully power represents a thermal fatigue cycle for certain parts of the engine but the amount of incremental damage caused by this fatigue cycle is determined by a number of factors: How hot is the engine and how fast the is power being reduced. If it is done aggressively then the incremental damage will be significantly bigger than the damage caused by a gentle and gradual power reduction. Thus the engine will consume a disproportionate amount of its total life compared to a more careful handling. A crack will not form immediately but an engine that is treated in such a harsh manner on a regular basis will for sure not reach the full TBO.
A few words regarding the physics of thermal fatigue and cracking:
It is not the cooling rate per se that counts but the temperature gradients that are built up during cooling, i.e. the inhomogeneity of the temperature field. Thermal stresses are caused by regions within a structure where free thermal expansion (or shrinkage) is constrained by strong temperature gradients. Strong temperature gradients are either caused by rapid heating or rapid cooling. In both cases high heat transfer coefficients are required. In case of rapid cooling high heat transfer coefficients are e.g. caused by a strong airflow inside the cowling as a direct consequence of a high air speed.
The situation is aggravated in regions where materials with different thermal expansion coefficients are mating (AL and steel) or at locations with high stress concentrations (notches, sharp corners).
On the other hand the susceptibility of a metal to fatigue damage  depends on the absolute temperature level at which the thermal stresses occur. The same temperature gradient in a hot piece of metal is significantly more damaging than if the metal is in a colder state.
Now we have all ingredients to get a better understanding of what shock cooling really means:
An engine that is very hot after a prolonged period of climbing under full power undergoes a rapid power reduction and simultaneously the plane is accelerated to a  high airspeed (imagine the descent of a tug plane after an aero tow). The airflow inside the cowling is significantly increased and the engine is cooled down rapidly (and inhomogeneously). The resulting heat flux induces temperature gradients and consequential thermal stresses in the structure. While for most of the structure these thermal stresses are insignificant there are a few life limiting spots like exhaust valve seats etc. where a certain amount of fatigue damage is evolving due to these stresses. The actual amount of fatigue damage is determined by the severity of the event, i.e. the hotter the engine, the more aggressive the power reduction after the climb and the faster the acceleration of the plane, the more damage will be induced.
Coming to my initial statement: I don't believe in shock cooling as a single event that could cause cylinder head cracking in one go but I do definitely believe that such events as described above consume a disproportionate amount of engine life and premature cracking is very likely if this sort of  mission profile is repeated too frequently.

Rapid throttle changes? Skydiving planes see a LOT of shock cooling, and they pay for it at overhaul time. And if you think cylinder heads don't dispose of a lot of heat, look at how cylinder heads evolved through the 30s-40s. The later R-2800 fins are finely machined, quite a contrast to earlier engines with cast fins.
And rapid throttle advance can eat you alive in some WWII planes. Many T-6's took their pilots into the weeds on TO. The BT-13 or PT-22 might snaproll if you got in a hurry with the throttle.

I worked at a piston-powered skydive center for 10 years - we didn't shock-cool anything. The pilot eases the power back about a minute before the drop and closes the cowl flaps. Engine temperature was a lot lower before the rapid descent. Our engines usually went to TBO without too many issues.

The T/O problems are however due to difficulty to compensate the sudden change in torque rather than any problem it would cause with the engine itself.

Another issue with a skydiving operation versus "normal" operations is that almost all of the time on the engine is spent in the climb, without the long periods of cruise (and relatively lower wear) that a normal engine sees.

Geared engines - those where the engine drives the propeller through a gearbox so that the engine can turn higher rpms than the propeller - are also susceptible to damage if throttle is reduced too rapidly.  You should never fly these engines so that the prop is driving the engine.  In other words, the airflow through the prop tries to drive the engine to a higher rpm.  Evidently the gear boxes are not built to take the forces in this direction.
So while flying a geared engine, throttle must be reduced slowly.  Appropriate use of the prop control lever can also help

Does this include Garrett TPE331 turboprops? If not, then why not?

rbp, I don't know if any turboprops experience this problem.  Perhaps their design is more robust.  Hopefully some turboprop drivers can comment.

Are aviation gear boxes that much more fragile than automotive gear boxes? I regularly use engine braking when driving, which does exactly what you're describing, @SkipMiller, except it's the wheels turning the engine instead of the prop.

I do this in a car, too.  I guess the answer to your question is "Yes".  There are a lot of Old Wives' Tales (OWT) in aviation, but I have never heard of the advice "don't let the prop drive the engine" described as an OWT.  Again, I hope some geared engine drivers can comment.

I have never experienced engine problems on descent, but I have experienced 2 engine failures shortly after take-off. One cylinder head crack about 5 minutes after take-off(C-150) and one stuck valve(C-172) less than a minute after take-off.
I cannot be sure the exact cause, but I suspect the rapid heating of the engine had the same negative effect, but in reverse order, of shock cooling.
Now, I make sure the engine is warm (via what ever is available...) before take off.  The checklist may say "eng temp in the green", but why not let it climb up toward the middle of the green a little further to allow the engine to expand a little more before adding full power on take-off? The engine still has some heating and expanding to do while at idle, and is about to heat rapidly once take-off power is applied.
Maybe the majority of the engine stress/damage happens at take-off, not on descent.

While this is interesting and related to thermal shock too, this doesn't answer the question.

In turbocharged engines, the impeller spins very fast (25,000+ RPM), has very small tolerances, and operates at EGT temps (since the compressor is driven by the exhaust gas).
According to the M20M (turbo Mooney) manual, these engines must be given a 5-minute cool-down period to ensure that the oil continues to circulate through the turbo, and carry away the heat.
The way I fly this plane is to reduce the mixture at the same time as the power when beginning the descent, in order to keep the temps up, and to increase the mixture slowly during the descent to bring the engine temps down.  Then at shutdown, I run the engine with the throttle completely back, and allow all the temps (CHT, EGT, oil, and TIT) to stabilize.  Once the temps are stabilized at the lowest power setting, no more heat can be extracted from the engine.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


text:
Why are vectors used for sequencing rather than speed control?
Why would ATC generally issue vectors instead of simply issuing speed reductions to aircraft? It'd seem more efficient to have aircraft flying less track miles, so is there any reason that speed control is worse than giving vectors to aircraft?

Well, speed is used for sequencing enroute (eg in NAT OTS) using simple Mach vs distance rules. Vectoring is better suited in an approach environment

@Radu094 Vectoring is sometimes needed enroute as well!

Let's say you have two aircraft that will reach the same point in space at the same time, and your job is to keep them three miles apart.  One way to do it is to calculate how many knots the second aircraft should reduce their speed so that at the time the first aircraft reaches the point, the second aircraft will have fallen three miles in trail.
Unfortunately for you, this means that you have to work a time-speed-distance-wind problem for every single aircraft that you, as a controller, handle.
Alternatively, you pick a point three miles away and tell the second aircraft to fly there.
Air traffic controllers are human, and humans are better at angles than we are at numbers.  The simplest thing for controllers is usually the best thing - they've got lots on their mind already without making them do math too!  This might change in the NEXTGEN air traffic network (where everyone has a GPS position and speed readout right there on the screen) but for now, easy is better than hard.

It is easier for an aircraft to change headings than to change speed, especially in situations that would require the aircraft to slow down and then speed back up repeatedly.  ATC is also restricted from slowing aircraft below certain minimum speeds until they get closer to the airport, so a vector may be their only option.
For instance, if ATC is trying to line two airplanes up on final and get them spaced a certain distance apart and going the same speed, a vector is usually the best tool because all they have to do is angle the following airplane correctly to intercept final and don't have to issue any speed adjustments.


text:
How do FAR 23 takeoff requirements compare to FAR 25 requirements?
What types of factors come into account when planning takeoff performance for dual engine aircraft under FAR 23, compared to the aircraft with certified takeoff distances under FAR 25
Obviously, the margin for light aircraft would be less, but does this difference make a significant change in the required (legal) distance or is it less that it seems?

Maybe this will help someone answer it: §23.53 and §25.113

@DannyBeckett worth a shot!

The single biggest difference is that FAR 25 has rules that pertain to wet runways. Aside from that, FAR 25.113(a) uses the greater of two tests to determine accelerate-stop distance:

(1) Accelerate to $V_{EF}$, then reject the takeoff
(2) Accelerate to the highest speed required for takeoff (somewhat unclear?), then reject the takeoff

...while 23.55(a) is more or less equivalent to 25.113(a)(1).
Comparing the three methods, the rules are mostly comparable. The only major difference is that under Part 25 "a distance equivalent to 2 seconds at the $V_1$ for takeoff from a dry runway" (25.113a.1.iv and 25.113a.2.iii) must be added to the other factors.
Because aircraft certified under Part 25 must use the greater of two different tests and add a distance equivalent to 2 seconds at $V_1$, accelerate-stop distances will likely be greater than for Part 23-certified designs that are otherwise similar.

For reference:

FAR 23.55(a)
FAR 25.113(a)


text:
What training is required for pilots conducting ASETPA operations?
In Australia, aircraft approved for ASETPA operations are certain single-engine turbines allowed to be operated commercially under IFR. While I understand that the manufacturer is required to meet a series of requirement, I'm not so sure about whether the pilots in ASETPA operations need special training or approval. Is extra training and/or testing required, and if so, how extensive is it?

According to the CASA AOC Handbook, section 15.3.1.2, pilots do need to have specific training. Most of this training is regarding engine failures and emergency landings, in some situations in IMC.

CASA requires that all ASETPA operators have a training and checking
organisation.
The CASA Inspector will verify that for ASETPA
operator’s the following additional procedures are included within the
training and checking organisation:

Engine failure or malfunction which necessitates stopping the aircraft on the ground
Engine failure or malfunction which necessitates an off-airport landing after take- off on the most suitable terrain in the vicinity of the aerodrome. These can be organised into a number of procedures, depending on the height of the aircraft at the time of the failure
Engine failure or malfunction which necessitates turning to execute a glide landing upon a serviceable runway, including a ‘turn-back’ manoeuvre. This procedure is to contain a minimum indicated airspeeds and altitudes
Engine malfunction, during climb, cruise and descent and from the approach to land phase in VMC and IMC
Additional procedures for the conduct of a forced landing in IMC to ground level

The next section discusses route limitations, which I am assuming the pilots should at least be familiar with.


text:
Which country has jurisdiction over incidents in flight?
If an incident occurs on board an aircraft in flight which could be considered as criminal in one country, what decides which country the incident falls under? For example, if a man was found to be in possession of "virtual" child pornography and not all of the countries involved consider that to be illegal, which country is the one who decides whether the person have broken the law or not?

Your example is murkier than you realize since he likely was in possession on takeoff and would be in possession on landing.  Instead try to use an example of a crime that he could commit during the flight, in a country's airspace, that doesn't necessarily also occur at both ends of the flight.

What if he draws the virtual child porn himself after the plane leaves the 12-mile zone of the departure country, and tears it into tiny pieces and flushes it before arrival? Or loudly announcing state secrets of the departure country? That's usually not illegal at the destination unless it's a departure-country flag carrier.

In my PPL class I was taught a simplified explanation:
If a baby was born (or a crime committed for that matter) on an aircraft, the official country in which it was born depends on wether the aircraft's doors are open or closed (within reasonable limits, so assuming they can't be open in flight).
If the doors are open, the country will be the country where the aircraft is currently located. If the doors are closed, it will be the country in which the aircraft is registered.

Not to rain on your analogy, but heavily pregnant women are typically not allowed to fly on planes, for this exact reason :p

Which makes perfect sense ofcourse :)

This is fascinating -- I'd be interested in seeing a source for this statement.

@DannyBeckett airborne births (and deaths) happen regularly enough that it's a standard part of flight crew training, and immigration in most countries have procedures for hours-old arrivals with no documents. Sometimes it's genuinely premature, sometimes it's deliberate - the mother has plans to get citizenship in the destination country and hits labour a couple of weeks early.

@paul That's interesting; I've yet to hear of an airline without a policy for the maximum weeks pregnant an expectant mother can be, to fly. Fair enough in cases where it's genuinely premature.


text:
What are the operational limitations on ADS-B DO-260A (as compared to DO-260B)?
First off, here is my understanding: I'm primarily concerned with retrofit aircraft.
A number of Asian countries (and Australia) already require ADS-B to DO-260A standard.
The European mandate is set for June 7, 2020 (DO-260B).
The North American (FAA) mandate is set for January 1, 2020 (DO-260B).
Am I correct in my assumptions?
After the deadlines, what are the operational limitations (assuming the aircraft is equipment with DO-260A)? Is the aircraft banned from the airspace completely or is it still possible to operate but get undesirable routing (such as low altitude or positioning)?
What is involved in upgrading to DO-260B? What are the differences between the standards?

Related: Can you ignore the 2020 ADS-B Mandate

What kind of aircraft? Only aircraft exceeding 5700kg MTOM or with a maximum true airspeed capability above 250 knots are subject to the ADS-B mandate in Europe.

When I asked this I was looking at CL600 (2B16/19) series aircraft with Proline 4.

If the aircraft is subject to the ADS-B mandate of Europe, it will not be allowed to operate in European airspace after June 7, 2020 if it does not have a certified EUROCAE ED-102A (equivalent to RTCA DO-260B) compliant ADS-B transmitter. Aircraft with a maximum take-off weight exceeding 5700 kg or maximum operating true airspeed exceeding 250 knots are subject to the mandate.
The USA rule is a bit different, as it allows ADS-B on universal access transceivers (UAT) below 18 000 ft which is different from the 1090ES technology used in DO-260. You can do without ADS-B in the USA after January 1, 2020, if you never fly higher than 10 000ft MSL (exceeding 10 000ft MSL is allowed as long as you don't exceed 2 500ft AGL), you do not enter or overfly class C airspace and keep further than 30 NM from class B airspace.
If your aircraft is 1090ES ADS-B equipped it must be DO-260B compliant; if it UAT ADS-B equipped it must be DO-282B compliant.
The difference between DO-260A and DO-260B are many small changes. This list is not exhaustive:

change in the way position integrity is encoded,
addition of barometric pressure setting,
new encoding aircraft length / width
change in encoding of speed on surface

Typically the update from DO-260A to DO-260B requires a firmware update and some configuration changes. However, note that the mandates include more requirements than just the ADS-B protocol version. There are requirements on the integrity of your position source (GPS) as well, and the maximum latency in the position transmission chain. In the worst case you are up for a rewiring of the GPS or even installing a new GPS.


text:
Passenger cabin asymmetric seating and balance
In the early 1990s I made many short haul flights in Short 360 aircraft. These had passenger seats set up as two rows on the right, one row on the left as per the picture.
Assuming a full load of passengers, what are the implications if any of having more weight on one side and if there are implications how would they address it ?

Yes indeed thanks, post as an answer and I'll tick it.

The certification requirement for control authority at lateral CG limits is only that the airplane have sufficient roll authority to trim to hands off level flight with the CG at the lateral offset limit, in the most critical case (usually single engine at V2+10).  You actually have a lot of room to play with.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
Do non-US citizens still have to get an additional TSA check?
I'm familiar with the rules requiring all non-US citizens to acquire TSA clearance, but as of 2016 the rules have been changed and it seems that everybody has their background checked by the TSA as part of the student pilot certificate application process.
Does this mean that non-US citizens no longer have to go through the separate background check, or will they now be checked twice by the TSA?

This is probably a dupe of this question. Essentially, nothing has changed for non-US citizens. The change affects US citizens, who now need TSA approval to solo, but not to start flight training.


text:
How can you fly at 0kts without stalling?
At 0g, stall is theoretically impossible.
In practice, can a maneuver be performed that, by bringing the aircraft to, or very close to 0g, also brings the aircraft to a temporary standstill, or near standstill, in terms of true air speed?
Can such a maneuver be performed without exceeding 30° pitch?
If so, how?

At 0g, stall is theoretically impossible. Are you in orbit or free falling? In the second case stall is happening already

@Jean "In the second case [free falling (assumed within the atmosphere where planed are capable of flight)] stall is happening already" Are you sure about that?  Take a look at a Coefficient of lift vs AoA diagram and explain why what is in quotes is incorrect.  A free-falling skydiver experiences more than  0g because of air pressure.  A stalled wing does not = 0 lift.

0kts is different than 0g.  I can have 0 knots ground speed flying into a very strong head wind and not stall at all.  I would recommend the title to make this more clear.

Also, you could go from straight and level flight and nose over at just the right rate and create 0gs, and dive nose down, and maintain 0gs for a few seconds with proper airflow over the wings (i.e. not stalled).

No, stalls can occur at any airspeed, attitude, or load factor.  All that is needed is to exceed the critical angle of attack and you have stalled the airplane.
Some places this can occur and does happen if mishandled by the pilot is at the top of inside loops, where the airplane can come very close to a zero airspeed if it's done wrong.  Another place this does occur is a hammerhead stall where the stall occurs in the vertical, just as the aircraft is at or comes very close to zero airspeed.

There is a massive difference between "No stalls can occur..." and "No, stalls can occur....".  That comma literally makes the sentence mean the exact opposite.

To wit: Eats shoots and leaves

You're asking 3 questions.

How can you fly at 0kts without stalling?

Have a thrust:weight ratio greater than one.  John Klatt's Screaming Sasquatch is one such airplane.

In practice, can a maneuver be performed that, by bringing the aircraft to, or very close to 0g, also brings the aircraft to a temporary standstill, or near standstill, in terms of true air speed?

Sure.  Pull to vertical (or near vertical) and wait.  You'll hit zero airspeed right before gravity reasserts itself.  As Carlo Felicione mentioned in his answer, a hammerhead maneuver will do this.  There are other maneuvers as well.  The main idea is to convert your forward momentum into a vertical climb and stop depending on the wings for lift.
When I perform a loop (I fly an aerobatic plane -- DON'T try this in a Cessna!) the aircraft is essentially ballistic across the top of the loop.  It will indicate 0 knots airspeed regularly (that's the trick to making round loops)

Can such a maneuver be performed without exceeding 30° pitch?

Probably not, and the fact that you're asking is kind of scary.
Probably not because you won't have enough upward momentum to offset gravity between the time your wings stop producing lift and when you hit zero airspeed.
Scary because these are aerobatic maneuvers, and attempting them in the wrong aircraft without training is stupid dangerous.

Thank you.  I was just asking out of curiosity.  The Screamin Sasquatch's vertical climb and the other aerobatic maneuvers are exactly the kind of thing I was interested in hearing about.  I'm confused about your last sentence though: Students regularly practice stalls and spins in non-aerobatic aircraft; is there anything more dangerous than that at <30° pitch and <60° bank?

"Is there anything more dangerous..." would make a good separate question.  The short answer is that it becomes really easy to over-stress the air frame, tumble the gyros, void your insurance, etc.

Being stalled is a property of the wing and the wing only, so thrust/weight ration has nothing to do with it. What thrust/weight ration greater than 1 does is allow maintaining altitude even if stalled—but the plane would still be stalled, it would just not lose altitude or control because of it.

@JanHudec You're completely correct.  I was thinking more in terms of "what will the pilot experience" rather than the formal definition of a stall.  How should I best improve this answer?  I read the question as "the OP wants to hit 0 IAS without falling out of the sky"

Can you fly at 0 knots airspeed? Sure you can. Helicopters do it all the time. It's called hovering. Technically speaking, it is flying, i.e. being held aloft by lift generated from airfoils. True that the airfoils are not stationary, but the rest of the aircraft is.
If you want to get picky and say airplane with wings, I present the V22 Osprey.
A pure aircraft can achieve 0 knots in the air, but technically speaking, it's not flying, because it's not being held aloft by an airfoil. It would be kept aloft either by pure engine power in the case of very high performance aircraft or non tilt rotor VTOL such as the Harrier or F35B, or as part of a ballistic arc. Neither mode of operation uses an airfoil for the duration of the zero kts airspeed, so neither would be 'flying' by the traditional definition.
Zero g, on the other hand, can only be achieved briefly at the top of an arc where the wings are unloaded, or in a dive. 45 degrees nose down, 360 KIAS, and you get near or at zero g. Popularly known as the vomit comet.

"Helicopters do it all the time": An helicopter in a vortex ring state is more comparable to an aircraft at 0 kt than an helicopter at 0kt forward speed with blades fully loaded.

I would offer that a tailslide would be a negative or zero-g maneuver. The aircraft is brought into a vertical pitch of 90° (exceeding the 30° in the question) and held through the stall with rudder alone. Once the tailslide begins, the direction of travel with reverse airflow is controlled by rudder alone. At this point the airspeed is negative with regards to the normal direction of flight but positive with relation to the aircraft as a whole (although in the opposite "wrong" direction). Recovery occurs when the rudder is offset allowing the tail to "slide out" from underneath the nose and snap the nose to the new direction of flight (down in this case).
Not sure if it answered your question but thought I'd chime in since I've seen this performed a few times.

0 knots of airspeed in a heavier-than-air fixed-wing aircraft and not stall? No.
0 knots of groundspeed in a heavier-than-air fixed-wing aircraft and not stall? yes.
0g and stall?  No a stall is not a 0g maneuver. Even if you were in a vacuum, there is no relative wind because there would be no air, hence no angle of attack, hence no angle of attack to exceed to enter a stall.  As soon as you leave said vacuum then the molecules of air are now applying some force to the airframe meaning it is no longer experiencing 0g, although this small force would be imperceptible to human somatosensory systems if they were onboard.
The reduction in g-forces are associated with stall recovery, which is done by pilot control input reducing the angle of attack causing the stalled condition to cease, and therefore, also reducing the lift while the aircraft regains kinetic energy by trading off its potential energy.  This reduction in g-forces is not technically a result of a stalled flight condition.
Stalls do not equal zero lift; keep that in mind.


text:
How can an airplane keep going forward if it has no thrust?
Every pilot is familiar with the basic model of aircraft forces:

If lift is greater than weight, the plane climbs, if less, descends.  If thrust is greater than drag, the plane accelerates, if less, decelerates.  In unaccelerated flight, all must be equal.
In an engine-out situation, there is no thrust, so if a constant glide ratio is to be maintained, I thought the plane must be pitched forward so the forward component of lift does the job thrust would normally do in cancelling drag.
However, in the Airplane Flying Handbook, 4-3, figure 4-2, it shows an example lift-drag diagram that shows $L/D_{max}$ ($= V_{BG}$) to be about $6°$ AoA.  Wouldn't that result in lift having a backwards component and slowing down the aircraft to the point of stall?
What am I missing here?

While I was posting this question, I worked out the answer: The aircraft is pitched nose-down, but AoA is still positive due to the relative wind.  Weight is what counteracts drag.  I'll leave this question here though incase anyone has a good explanation or diagram to share.

AoA and pitch angle are not the same thing.  You can have +6 degrees AoA and still be descending.

It is the same as this question -- see this answer-- https://aviation.stackexchange.com/questions/56352/what-produces-thrust-along-the-line-of-flight-in-a-glider/56371#56371

Does space shuttle count?

@Zaz I have explained this question well.  Suggest to comment.

@user3528438 The shuttle was also a glider when it returned.

Angle of attack is not equal to pitch angle. Yes you can decompose weight into a forward and a perpendicular component - to airstream! Or you can draw lift relative to airstream.

In this drawing, pitch angle is zero and AoA = 6 deg. Lift now has a forward component relative to gravity.

Do you mean L is pushing the glider to overcome the drag?  How do you comment on my answer?

Lift L has a forward component, indeed.

Is the forward component of L horizontal?  Since L is perpendicular to the flight path, the forward component of L must not be parallel to the flight path.

L and D are by definition always measured relative to airflow, not to flight path.

So is L perpendicular to the air flow or parallel?

If at zero airspeed and zero absolute altitude this were to happen, then yes the aircraft would stall and be incapable of flying.  Then again, at this point, it would not matter, AS THE AIRPLANE IS ALREADY ON THE GROUND IN THIS STATE.
In all seriousness, though, the airplane would not slow and stall unless you attempted to remain at a constant altitude.  In a constant airspeed glide, however, where the airplane is descending at a shallow angle relative to the ground, it can be shown that the force of gravity is no longer perpendicular to the longitudinal axis of the aircraft and will have a component vector which is parallel to the longitudinal axis and opposed to the direction of both the induced and parasite drag vectors.
Another way to think of this is to consider the energy state of the airplane at the time the engine quits.  Its total energy is the sum of its potential energy, proportional to its absolute altitude, and its kinetic energy, proportional to the square of the groundspeed.  Once engine thrust is lost, that energy state begins to be drained away by the force of drag applied over a distance.  In order to maintain airspeed, the aircraft must begin to convert its potential energy into kinetic energy, causing the airplane to descend slowly until it reaches the ground.

The weight $W$ of the glider has two components, $Wt$ and Wn. $Wt$ is in the same direction as $V$ and $Wn$ is perpendicular to $V$.  Aerodynamic $F$ also has two components $L$ and $D$, where $L$ is perpendicular to $V$ and $D$ is parallel to $V$.
When $L = Wn$:
$Wt> D$, the linear acceleration of the glider is positive; $Wt <D$, the linear acceleration of the glider is negative; $Wt = D$, the linear acceleration of the glider is zero.
Some people think that there are only $L$, $D$, and $W$ on the glider. This is not entirely correct.  Simply put, there are only two forces on the glider: one is aerodynamic $F$, and the other is gravity $W$.  $L$ is only the component of $F$ in a direction perpendicular to $V$; $D$ is only the component of $F$ in a direction parallel to $V$.  Some people think that $Wn$ does not exist, which is also incorrect.  $Wn$ is the component of $W$ in a direction perpendicular to $V$; $Wt$ is the component of $W$ in a direction parallel to $V$.

What pushes the block downward?
 $V$ is the speed at which the block moves downward.  The weight of the block has two components: Wn perpendicular to $V$ and Wt parallel to $V$.  $L$ is the reaction force of the slope (inclined plane) on the block.  It is not the $L$ push block that moves downward, because $L$ has no component in the direction of $V$.  Wt is the force that pushes the block downward.

@quietflyer I said everywhere.

@quietflyer https://aviation.stackexchange.com/q/77543/42162

Just put the drag vector in there (from surface friction and air).  Add a little oil to the surface.  Repeat and observe V.

Here is a simple way to think of this problem:
Without thrust from its engine, the airplane begins instead to "coast downhill" like someone on a bike- and the pilot can choose whatever "slope" he or she wishes to follow, consistent with the need to keep the wings generating lift and the control surfaces to  generate directional control forces.
In a gliding descent like this, the weight of the plane times its descent rate in feet per second yields the horsepower being burned off by drag at that combination of pitch attitude and airspeed.
So in unpowered flight, the airplane flight manual will specify the best glide angle for a given load which minimizes drag and hence maximizes the time aloft- and thereby furnishes the pilot with the best opportunity to pick out a suitable landing spot.


text:
Do you need a rotating beacon if you have strobes?
If I were to replace my left nav light with a SkyBeacon ADS-B + strobe, could I remove the rotating beacon at the top of the tail?

No. For one thing the strobe would not be visible for 360° like the beacon. And if your plane came from the factory with a rotating beacon, I pretty sure that it is part of the Type Certificate so you would need some sort of approval to get rid of it. e.g. Field approval, STC with the SkyBeacon.

@JScarry: Thank you. If you post it as an answer I'll accept it unless someone has something better. Where do I find the details of the type certificate?

I am fairly confident that I am right, but I don’t  have sources to back up my comment, so I don’t feel comfortable posting it as an answer.

Skybeacon also offers an ADS-B install that goes on top of the tail. You must have the 360 degree visible beacon on the aircraft.

@MikeBrass The tailBeacon replaces your white nav light. It is available for experimental aircraft now and soon for certified.  I haven’t seen any information about a strobe from them and it is not listed on their website.

As required equipment for night flight, that’s technically feasible to do as this can serve as an anti collision light, provided the aircraft still has position lights and landing lights.  However, if you’re flying a certified aircraft, unless you have an STC to deactivate the beacon, you cannot as it’s listed in the minimum equipment list for the aircraft.  You’d be opening a can of worms to do so and there really seems to be no significant advantage in doing so.

I could be wrong, and I don't mean to be nit-picky, but I don't think this would be called a "minimum equipment list" in this case. I think it would be "marked as required equipment in the AFM", or something similar.

From: Electronic Code of Federal Regulations
91.205 parts (b) and (c), excerpted below, require a position light.  I believe it is a position light and it is needed. Call the FSDO office in your area and confirm. If they say Strobes, which pilots often turn off on the ground while taxiing to avoid blinding others, while the beacon light is on all the time as a reminder that an engine is running, can replace the beacon, than go for it.  Get it in writing to satisfy the A/P that will sign off the removal in your aircraft maintenance logs.

91.205   Powered civil aircraft with standard category U.S. airworthiness certificates: Instrument and equipment requirements. (a)
  General. Except as provided in paragraphs (c)(3) and (e) of this
  section, no person may operate a powered civil aircraft with a
  standard category U.S. airworthiness certificate in any operation
  described in paragraphs (b) through (f) of this section unless that
  aircraft contains the instruments and equipment specified in those
  paragraphs (or FAA-approved equivalents) for that type of operation,
  and those instruments and items of equipment are in operable
  condition.
(b) Visual-flight rules (day). For VFR flight during the day, the
  following instruments and equipment are required:
(1) Airspeed indicator.
(2) Altimeter.
(3) Magnetic direction indicator.
(4) Tachometer for each engine.
(5) Oil pressure gauge for each engine using pressure system.
(6) Temperature gauge for each liquid-cooled engine.
(7) Oil temperature gauge for each air-cooled engine.
(8) Manifold pressure gauge for each altitude engine.
(9) Fuel gauge indicating the quantity of fuel in each tank.
(10) Landing gear position indicator, if the aircraft has a
  retractable landing gear.
(11) For small civil airplanes certificated after March 11, 1996, in
  accordance with part 23 of this chapter, an approved aviation red or
  aviation white anticollision light system. In the event of failure of
  any light of the anticollision light system, operation of the aircraft
  may continue to a location where repairs or replacement can be made.
: : :
(c) Visual flight rules (night). For VFR flight at night, the
  following instruments and equipment are required:
(1) Instruments and equipment specified in paragraph (b) of this
  section.
(2) Approved position lights.
(3) An approved aviation red or aviation white anticollision light
  system on all U.S.-registered civil aircraft. Anticollision light
  systems initially installed after August 11, 1971, on aircraft for
  which a type certificate was issued or applied for before August 11,
  1971, must at least meet the anticollision light standards of part 23,
  25, 27, or 29 of this chapter, as applicable, that were in effect on
  August 10, 1971, except that the color may be either aviation red or
  aviation white. In the event of failure of any light of the
  anticollision light system, operations with the aircraft may be
  continued to a stop where repairs or replacement can be made.
(4) If the aircraft is operated for hire, one electric landing light.
(5) An adequate source of electrical energy for all installed
  electrical and radio equipment.
(6) One spare set of fuses, or three spare fuses of each kind
  required, that are accessible to the pilot in flight.

Previous was deleted, this replaces it.

You know, I don't think I have any fuses left in my plane, I think everything has been updated to circuit breakers.

The uAvionix SkyBeacon replaces the left nav (and strobe, if present) light; the optional companion uAvionix SkyLight replaces the right nav (and strobe, if present) light.  Together, they would provide 360° strobe and thus qualify as an anti-collision light system, making a rotating beacon technically unnecessary.
However, even if removing the beacon is legal, first consider whether it's a good idea.  Without a beacon, you would have to run the strobes continuously, i.e. during the day and even on the ground, not just in the air at night.  Running strobes on the ground is a distraction or even blinding to other pilots and therefore not consistent with safety.  While that may be an acceptable (to the FAA, at least) compromise for planes that never had a beacon, to avoid grounding much of the GA fleet until they pay to have one installed, IMHO it is not reasonable to deliberately remove a beacon to take advantage of that loophole.
TL;DR: Keep the beacon.


text:
Is it feasible to repair a C152 that flipped onto its back?
So there's a C152 that was tied down and blew over onto its back, suffered some damage to its wings (but electric flaps still work) and significant damage to its stabilizers.  Can it be fixed by replacing the stabilizers and wings?  What else would need to be done aside from repairing obvious damage? E.g. Would it require eddy current testing or any other kind of test for hidden structural damage?
Would there be any lingering safety concerns?  How much diminution in value would there be if damaged components are completely replaced?

Anecdote: the club I use to fly with had a C152 Aerobat that was flipped over on a landing by a student pilot. The plane was repaired and returned to service, and the pilot went on to complete at least her private. I think she may have even flown the same plane for the last part of her training, but I can't remember for sure.

That would be because the insurance company paid for the repairs, likely deciding that the repair cost+salvage value wouldn't exceed the hull value in that instance.  A wreck that becomes available for sale would mean the insurance company decided it was cheaper to pay out the hull value to the owner, and sell the wreck to Zaz or more likely to a salvager. A chum once bounced his '68 Cardinal (modded to 180 hp), and bent the NG, firewall + prop strike. Insc paid out, 60K (which was over mkt value for that particular model).  Nobody was hurt and he wanted a bigger plane, so he was a happy clam.

Yes it can be fixed by replacing the stabilizers and wings which just bolt on. Replacements are readily available in the used parts market for 152s.
Generally with metal that's been subject to a single potential overload, if it's not permanently deformed, it's fine. So the only repairs required are to things that are damaged.  You would certainly want to do a careful inspection of the fuselage structure for any kind of deformation or overload-related cracks.
I don't think any NDT testing is required, but that would be up to the guy who signs off the work.  Maybe some dye penetrant testing of the main wing and stabilizer attach area structure to detect overload cracks, something like that.
The effect on market value is negligible for a Frankenplane if the repair was done properly, everything is documented properly, and the plane flies well. You'll probably take some hit, but if it has a fresh paint job and looks fabulous, probably not too bad.

The question is, is it worth it to do it if you come across a wreck.  You'd have to price the job out.  I suspect that at the level of parts replacements involved, it's not. Which is why the insurance company wrote it off in the first place.

Basically it's feasible, probably would cost more than it's worth to fix.

A potential candidate would be an airplane that is in fantastic near pristine condition other than the storm damage, terrific low time engine, prop not bent, won't require a full repainting except to make the replacement parts match (white), so all you do is bolt on the replacement parts, paint them, and go.  Helps if you can do most of the work yourself. If it requires significant overhaul/repair work, maybe, if you do the work yourself.  If you have to hire all that out at 70 bucks an hour, forget it.


text:
Can you get cheaper insurance with more experience?
I was exploring renters insurance on the AOPA insurance website and noticed that while you get a 10% discount for having no claims, there seems to be no difference in price between a private pilot with 50 hours and an ATP pilot with 5000.  Why is it not the case that more experience yields cheaper insurance?  Is this normal for aviation insurance?

There is no causality between the number of hours and accident rate. It may even be that higher hour pilots are slightly more predisposed to an accident because of complacency.

At one time, CFI rates for rentals were less.  But that was one company that I know of.  And it was a while ago.  My understanding is that aviation insurance underwriting is much less "tuned" than with other risk categories.

Related

It's not at all clear that more total flight hours correlates to lower risk. Data shows that pilots with <200 hours of total flight time are at the lowest risk of having a serious accident.
One can speculate the reasons for this, but the truth is, aviation accidents are still very rare occurrences. This makes gathering and analyzing data difficult. The data is very noisy due to the low sampling rate.
That said, statistical data points to a low rate of accidents until somewhere between 100 and 250 hours. Then it increases steeply, reaching its highest point around 500 hours for non-instrument rated pilots, and 800 hours for IR.

Annualized non-IR GA accident rates (median TFH=250.5)*

Figure 11. Annualized IR GA accident rates (median TFH=823.5)*
Statistics have long shown a "hump" in accident rates at the middle zone of experience.
From there it descends slowly over time but never reaches the low rates of new pilots. Another thing that occurs is that the number of pilots at a particular level of experience decreases extremely rapidly after a few hundred hours. It decreases to the point where the number of pilots with high hours is very small. The sample rate is then so small that it's close to impossible to come up with an accurate risk assessment.
Additionally, sometimes insurance rates are obviously driven by factors other than risk. Most aircraft insurance will give a discount for instrument rating. But if you look at the above graphs, IR pilots are at a higher risk than non-IR. They can fly in IMC, which is higher risk, but they have cheaper insurance. This is clearly a marketing decision. If one insurer gives you that discount where others don't it will attract more customers.
* Source: Predicting Accident Rates From General Aviation Pilot Total Flight Hours,William R. Knecht
Civil Aerospace Medical Institute, Federal Aviation Administration

I suspect if you built the same graphs with the number of active pilots with that number of hours, the graphs would look almost identical to the accident rate graphs. In other words, there are few active pilots with low hours (if they are active, they won't have low hours for very long), ramping up to a point, and then as the hours get larger, there will be fewer pilots with that larger number of hours.

@GregTaylor the number of pilots at a particular level of experience decreases extremely rapidly after a few hundred hours That's what the statistician that drew the graphs did his best to correct for. There are, at any given point, several times more low time pilots than high time pilots. Data on non-accident pilots is very difficult to get.

It looks like these graphs are for the accident rate per pilot per year. Could the hump effect be explained entirely by the fact that inexperienced pilots probably spend less time flying, thereby exposing themselves to less risk? In other words, if someone hypothetically made a chart of accident rate per pilot per flying hour, is it possible that the accident rate would be decreasing over the entire range? (Never mind the question of whether or not it's actually feasible to create such a chart.)

@TannerSwett First, I'd say newer pilots fly more, not less. Most pilots with high hours are commercial or atp and I would think spend less time flying their own plane. But that's just my conjecture. More importantly, insurance is sold by year, not flying time. So that's what matters to the insurance company.

I would also say that low hour pilots are more likely to have an instructor with them, so mistakes might be less likely just because the extra set of eyes

My guess would be that if a pilot flies more hours per year, that pilot probably also has more hours of experience. But we're both just guessing here, and some data would be nice. I'm aware that insurance companies don't really care about accident rate per flying hour, but I'm still personally curious.

I will speak from some personal recent experience in getting quotes for planes I have been looking to purchase. I dont have any charts or hard stats but I have spoken to numerous insurance companies via AOPA and others I have used for my gap insurance. For some background at the time I had about 80 hours all pretty much in a PA-28-181 (archer), PPL VFR only. I was/am looking to buy a Mooney M20C/E (the insurance companies view these the same) and other similar 145Kts ish, light retracts. One of the most important things I found is that most online "calculators" are just estimates, get on the phone and talk to a broker the reality is VERY different...
There are a few factors that effect insurance rates:

Time In Type
Ratings/Certificates Held
Hull Value

I asked the insurance brokers point blank "what can I do to bring my rates down?" and in all cases they answer, "add time in type". An instrument rating would bring my cost down by about 10% across the board and subsequently increase my hours. If I had time in type (in aircraft model) that would bring my rates down about 10%ish as well. Adding time in the archer VFR only would not effect my rates for a different air frame like the Mooney. Most insurance companies will also stipulate some mandatory instruction time before you can carry passengers. If you actually apply for a quote as a 50 hour VFR pilot you will get a very different quote than a 5000 hour ATP. The base insurance on the air frames hull value may, however be consistent.
Most applications also ask for total hours in the past year as well as total hours over all. i.e. they want to know how much you have flown recently which they put importance on.
If you poke around some of the aviation forums you will find stories of huge insurance drops after a year of ownership and time in type as well as stories of hikes for no apparent reason.
On the topic of gap insurance. Generally speaking you get gap insurance (renters insurance) to cover the deductible on the flight schools insurance. My FBO/Rental facility has a 10K deductible (their policy covers beyond that) the renters insurance covers me from 0-Deductible min as well as some passenger liability. The price (for the past few years) despite my increasing hours has held fairly constant which is a bit contradictory to the rate patterns for personally owned aircraft. Keep in mind this is not air frame limited and extends to any aircraft Im legally aloud to fly/rent.

What an excellent commentary Dave. 'have flown recently', I've noticed that a ton of crashes, (which affects insurance calculations), are due to older pilots with very low recent experience... I mean 20k hour atps, 70+, getting into an old plane with maybe 3 hrs pic exp over the last 3 months.  This really hurts GA insurance rates.


text:
Is it possible to use Morse code for communication?
Let's say your radio fails, but luckily you brought your keychain Morse code transmitter as a backup!  Is there any way to use it?

ICAO defines Q-codes for aviation use.  Q-codes were initially designed as Morse code abbreviations.  But I can't find any information on if and when Morse code was officially discontinued for aviation use.
Where is the record of Morse code being discontinued in aviation or, if it is still possible to use it, how do you use it?

What do you need to communicate, and with whom? I doubt you can call ATC. You might reach a ham radio operator who could call them on the phone and relay information, but that's going to be difficult with such a low power radio. Also, how are you deploying your 255-foot-long antenna while in the air? Overall, this is theoretically possible, but I think the result will be that you focus too much on communicating at the expense of aviating and navigating.

Is that thingy transmitting only on 1.8432 MHz? That seriously limits the practicality... If the tx frequency was selectable and an antenna was carried (because why not), then for sure it could be used.

Is that thing an actual transmitter? It looks to me like it's intended to feed into another piece of equipment, like an actual radio transmitter. If it was an actual transmitter it would have an approval sticker on it. (Frankly it looks like it's a toy, but feeding into another piece of equipment is the only use I can think of.)

@Someone: That's what I suspected, that all you would be able to reach is Hams. I know the wavelength is very large, but antennas can be made to be much smaller (by coiling them, etc). Is it not possible to make one that is handheld?

@DJClayworth: Yes it is a transmitter with built in morse code paddle. You just plug in a battery and antenna.

@Zaz that's already a very low power radio (0.016 W). For comparison, 5 W is generally considered low power. Antennas can be coiled, but they become much less efficient, and antenna efficiency is especially critical with such a low transmitter power. A handheld 160 meter band antenna that could achieve usable communications at 0.016 W is almost certainly not possible unless all other variables (distance to other station, ionospheric conditions, space weather, etc) are ideal. Another problem is that that is only a transmitter, so unless you also have a separate receiver, you will not hear any..

...responses from other hams. That might not seem important, but if whoever is helping you needs to ask for more information, you won't hear their question.

Morse Code is still used in aviation to identify navigation aids by audio means. VORs and NDBs broadcast their identifier letters as beeps heard on the audio channel when you tune in that VOR.  You are supposed to listen in to confirm the station you are tuned into when you select a nav-aid while IFR flying.
Nobody actually learns to interpret and transmit Morse code (maybe, pilots or controllers who are ham R
radio enthusiasts), beyond the Mayday signal of SOS. Navigation charts show the Morse version of their 3 or 4 letter identifier, and the audio broadcast of the dots and dashes is very slow to allow pilots, almost none of whom know Morse, to listen to the beeps and follow the Morse on the identifier box on the chart (until they get to know that particular navaid by ear).
If I was in some kind of emergency where I couldn't communicate by voice, only microphone clicks, I would certainly try sending Morse over the air by mic clicks if I knew how. And there's a possibility somebody listening in could be able to interpret the letters or at least record it for later interpretation.
I decided years ago that I'd learn the Morse alphabet for that reason, and just for kicks. For those that are interested in acquiring pointless knowledge, you can learn Morse letters fairly quickly by creating a list of words or short expressions that match the cadence of the Morse letter, the sillier or otherwise memorable sounding the better.
For example:
A = . - = A-chooo
B = - ... = Browwwn-cho-co-late
C = - . - . = Chaar-lie Chaar-lie
D = - .. = Daaag-nab-bit!
E = . = Eh?
F = ..-. = Funny-haan-dle
G = --. = Goood goood grief
H = .... = Ha ha ha ha
I was able to recall those letters right away, and I haven't really thought about them for 10 years or more.

I entered ATC in the 80's and learning Morse code was not a requirement then. It is doubtful that more than a handful of controllers nationwide know Morse code.

I kinda figured that. I tried out once in Canada in '86 and took the preliminary screening test. It was a booklet of diagrams of radar displays with various target tracks, & a table of their speeds/alt/routes, & you had to pick which targets would conflict, on a time limit. I got 44 out of 50, 2 wrong, & 4 I didn't answer because the test ended before I was done and I wasn't paying attention to the time. Pass was 40, but they told me I didn't make the cut b/c they had so many applicants they were cutting off at 45 for follow up testing. Prolly would've made it if I'd checked them off randomly.


text:
Why is there a blue square on top of the 2Q9 airport symbol?
What is up with the sectional symbol for Dyer (2Q9)?  Why is there a blue square on top of it?

The blue square is the symbol for the Dyer DME

Why?
The discontinuity is because Dyer is extremely close to the intersection of the San Francisco and Las Vegas sectionals, and the AirNav/Avare software probably discarded that inch of pixels when it merged the two charts.
For reference, here's where Dyer is on the Las Vegas sectional.

I did not know this is how they depicted DMEs on unpaved airports. Thank you!

Do you know why AirNav and Avare don't display the DME info box and have discontinuities in that area?

@Zaz - Because it's where two charts meet.  See updated answer.

Wow. I always assumed the FAA had accounted for electronic maps and released a properly stitched-together version. I guess not.


text:
What do you need to know to fly a Cessna?
I've almost finished ground school and am about to start flight training.  I'd like to show up fully prepared, so am compiling a list of things I'll need to know to fly a C150.
I was hoping someone knowledgeable could point out anything I've missed.  One point specifically is checklists: I read a good article once by a military pilot who argued for completing all procedures from memory, then checking them using the checklist (hence the name checklist).  Is this a controversial approach?
The things I think I should know on day 1 are:

Vso, Vs, Vfe, Va, Vno, Vne; Vr, Vx, Vy
Procedures: Walk-around, pre-flight, emergency procedures, pre-landing
Airport: Taxiway layout, communications
Skills: Taxi, takeoff, turns, mushing, landing

Any other tips on how to best prepare myself before getting in the cockpit would be welcome.
Thank you.

Personally I think this is too broad, but as an anecdote my first instructor said that he often had "issues" with students who were over-prepared. They tended to either have the wrong information or be thinking about it in the wrong way, rather than listening and learning. That's not to damp your enthusiasm, and for some students it worked, but please listen to your instructor first.

You're on the right track, but let your instructor guide you along the path of righteousness or you'll end up thinking about all the stuff rattling around in your head instead of listening to what they're telling you while they're trying to show you how to fly. Day 1 is largely just familiarization - you're not going to need to know all that detail. They'll have a syllabus that will include everything you need to know, and they should be able to guide you on what'll be good to focus on for the upcoming lessons.  The private pilot practical test standards are a great preview of what will (eventually) be expected, and if your ground school works you should be through the written and aware of any weak academic areas soon enough to correct any knowledge deficiencies that may bear on your flight training.  Definitely read the POH cover to cover so you know what's in there (but you don't have to memorize it all!), and ask your instructor about anything that doesn't make sense.  Listening to the tower on a handheld or through LiveATC.net may be useful (you'll find they're probably doing the same thing over and over and over) to understand what to expect, and the Aeronautical Information Manual is full of useful information that may go beyond what was specifically covered in ground school or on the written.  ATIS and/or ASOS/AWOS broadcasts are usually available on the phone, so listen to them until you "get" it all.  That should save time in the airplane.
The instructor should also cover checklist procedures, and will know what local examiners expect you to do to pass.


text:
What long-range jet is easiest to fly?
Of jet aircraft with sufficient range to cross the Atlantic on a full tank of fuel, which is easiest to fly?
More specifically:
The required range is from New York's JFK Airport, to Shannon Airport, which is just over 3000 miles.
Cost of the aircraft is irrelevant for my purposes, as my fictional protagonist intends to steal one. So from that perspective it could equally well be a Learjet or a 747. However, he is a novice pilot with minimum training. Is a smaller jet easier to fly?
The story is set in 1986, so it needs to be a plane that would be available then. But pointers to suitable aircraft nowadays would still be useful; I can backtrack to contemporary equivalents.

Will he steal the plane with a full tank of fuel, or at least enough for the flight? If not, and he doesn't have a way of also stealing fuel, the cost of the fuel will be a major factor.

Jet fuel was about $0.50/gal in 1990 (https://transportgeography.org/contents/chapter5/air-transport/jet-fuel-prices/), so much less than now, but the cost will still be significant, especially considering that $0.50 in 1990 is 1.04 in 2021.

@Someone Right, yes, for the sake of plot convenience, he finds a plane that has a full tank of fuel.

I'd go with a Blackbird

Are you considering whether the aircraft is rated for single pilot operation?

@Jim I was under the impression every plane can be flown by one pilot, it's just that big passenger jets are legally required to have two as an extra safety measure in case one becomes incapacitated. Is that not the case?

@rwallace I think on some planes not all controls are accessible/reachable from all crew stations.

Just one pilot?  That rules out all airliners with sufficient range.  Start with a list of bizjets of the era certified for a single pilot.  I don’t think you’ll find a significant difference in difficulty between them.

I can't imagine, @sophit, that the Blackbird falls into the category of "easy to fly". Though, I've been wrong before...

@FreeMan: just kidding  Anyway it had a stability system and a quite "standard" cockpit.

Perhaps a Ryan NYP, single pilot, easy to fly, pretty simple controls, can make the flight, however, its not a jet...

Sadly this only fulfils your "easy to fly" criteria.  Max range is ~1200nm and definitely not 1980s, but just in case your question has piqued any interested in small, easy to fly jets - this is a beauty.  Cirrus SF50 Vision Jet.  6/7 seats, single engine, can be flown by a single pilot, starts with a single button press, has an "auto-land" button for the passengers to push if the pilot becomes incapable...

I'm not too familiar with business jets of the 1980s, but from an airliner perspective, that would probably be the 757 or 767. A single pilot could easily manage to fly either one.
However, if you're trying to go for keeping it real, a "novice pilot with minimal training" (by which I assume you mean someone taking flying lessons in a Cessna)...not a chance. Wouldn't even be able to figure out how to get the thing started...taxi it to the runway and take off without crashing it would be a whole different story, to say nothing about managing to land it. The entire idea is just absurd, I'm sorry to say.
That would be true for any jet, not just an airliner. We're talking exponentially more complex airplanes than one your protagonist would be learning to fly in. Just navigating it across the ocean would be far beyond the abilities of a novice student pilot, and figuring out how to program the FMC or even understanding how to initialize the IRS (or even knowing what a FMC or an IRS is in the first place) would be like a 7 year old trying to read Attic Greek. You might just as well ask a novice pilot out in orbit in the Space Shuttle to get it back on the ground in one piece.
BUT...authors need poetic license, so if you're going to gloss over that bit of detail...the 767-200 was in service in 1986. The 757 was also in service, but there weren't as many of them around in the US until more like the late 80s. Regardless, both the 767-200 and the 757 would be flyable by one pilot, they are very automated (quite advanced for their day), both could easily do a JFK-SNN leg without even needing a full tank of gas. Based on my experience flying both, I'd take a stab at saying you could do that leg with something like 50k to 60k pounds of gas in the 757, maybe more like 75k to 85k pounds in a 767-200.
Any other type of airplane in that time period (747, L-1011, DC-10) that would be able to do transatlantic flights would have been a 3 pilot airplane with a flight engineer panel that would pose a significant problem for a single pilot to operate. It wouldn't be insurmountable if the pilot really knew what he was doing, but it raises the bar even higher for a "novice" pilot.

The Airbus A310 and A300-600 were also available in 1986. Both only require 2 pilots (no flight engineer) just like the 757/767 and can easily fly between US east coast and Ireland.

I agree with Chris above. The B757/767 is a user friendly aeroplane for experienced pilots to operate.
I reckon you could teach a competent multi-engine IFR pilot to fly one to a basic airline First Officer standard in a few months.
However a novice pilot would just be overwhelmed if he or she could get in one and even if someone could get the engines started and manage to taxi it, everything would happen so fast on takeoff and initial climb that a bad outcome would be highly likely.
A successful manual landing would also be highly unlikely. The human brain can easily be overloaded if ‘thrown in the deep end’.
If the fictional character could get some instruction in a real airline simulator the scenario would be more plausible.
A private pilot or advanced student with some simulator training could plausibly learn how to program the FMC and get a B767 into the air, get the autopilot on and fly across the Atlantic.
The aircraft will do a full automatic landing if the airport has an ILS and is set up and operated correctly, but it would take at least a few days of simulator training to be able to do a complete flight.
Using a Microsoft flight simulator with a B767 add-on, and there is a good one, could be used to learn some of what would be needed.
The desktop simulation is good enough to learn how to get the a/c going from ‘cold and dark’, program the FMC, use the autopilot and quite a bit more but translating that to the real aeroplane for a complete real flight would be a big stretch. Implausable IMHO.
Also the good B767 add on for the MS flight sim was not available until about 2000.
BTW, it is plausible to me that the 9-11 murderers chose the 767 and 757 because that add-on allowed them to learn the FMC, autopilot and glareshield Mode Control Panel. But their plans did not include taxiing, takeoff, cleanup, approach and landing.
I would not like my family to be in the back of a jet that I had no experience of operating if I was forced at gun point to do it by myself, and I have 22 years of jet airliner experience.
A cousin of mine who was an Air Force maintenance engineer got his father into a B707 simulator at least a few times in the '90s. (Not in the USA). They flew it for hours, with motion off. If they could do it, so could your fictional character. You don't need the hydraulic operated motion (which would be bound to attract attention) on to run the software and have a realistic trainer.
Around 2008 my sim buddy and I went to another country for a B767 type rating. After the ground course we were scheduled for sim training but our (own airline) instructor was delayed.
The technicians were happy for us to fly the simulator with the motion off (no wear and tear) and we started our own training. We had the manuals and I had a Microsoft flight sim with the 767 add-on on a laptop in the hotel room. This helped a lot and we had already flown other jets.

I can’t think of any aircraft that would fit that criteria. Airliners from that era required a three man crew to operate.  And very few business jets had that kind of range.  About the only business jets I can think from that era that would satisfy those needs would be a Gulfstream III or IV.  And even there, a novice pilot with a minimum training would probably not be able to operate that kind of an airplane successfully for a transatlantic flight.


text:
Malaysia Airlines Flight 370 - Why didn't Malaysian Air Force scramble jets?
It seems odd that a large commercial aircraft can deviate radically from its scheduled flight path without the military doing something about the situation. Malaysian military radar tracked the plane for about an hour after said aircraft had dropped off the air traffic controllers radar.
Why were no jets scrambled?
Has Malaysia not heard of "9/11", and how commercial aircraft were used by terrorists?
Which other countries military also pays such little heed "9/11"?

Welcome to SE.Aviation. This is largely an opinion based question, however you may be able to reword it to make it fit within our guidelines if you are curious about Malaysian jet scrambling protocols please word it as so.

Which other countries military also pays such little heed "9/11": The question is provocative, but the answer is sad. Many countries are more concerned about not dying before being 40 years old, and eating something, than looking for a threat that will never come because it wouldn't move anyone to tears in wealthy countries.

You can't really blame the Malaysian Air Force as they only monitor Air Force aircraft, not a random civilian jet flying off route.

There are multiple reasons for this:

The aircraft stopped communicating after the Kula Lumpur asked the aircraft to contact Ho Chi Minh ACC. The last verbal contact with the aircraft is this:

Lumpur Radar: "Malaysian three seven zero, contact Ho Chi Minh one two zero decimal nine. Good night."
Flight 370: "Good night. Malaysian three seven zero."

The Kula Lumpur Control had no way of knowing whether the aircraft had contacted as instructed (and acknowledged).

According to the Malaysian defence minister, the aircraft was deemed commercial and not hostile.

Even if the aircraft was tracked in radar by the military, that in itself is not sufficient for scrambling jets. Usually, the ATC will inform the authorities about any possible deviation; It is unlikely that the military would have real time details of aircraft routes. Note that it was not possible in this case (the aircraft transponder had gone silent before deviating from path). Also, there can be multiple reasons for loss of communications (usually equipment failure), and one does not immediately conclude that the aircraft has been hijacked.

Scrambling jets is usually the last resort and are sent to shoot the non-responsive aircraft. You don't shoot a civil aircraft with hundreds of passengers just because a microphone stopped working. The ATC must confirm that it had deviated from path and then the aircraft must be deemed a credible threat.

While the procedures for scrambling military aircraft are usually classified, it can be assumed that they are different in case of US (and Europe) and rest of the world. It takes a lot of resources to keep aircraft and pilots ready to intercept aircraft, which not all countries have (or even require most of the time).

Fighters are not sent to shoot the non-responsibe aircraft. They are sent to identify the aircraft, check what kind of problem it might have and guide it to suitable nearby airport. They can shoot it as their last resort if it does not respond to the visual commands either, but they have many tasks and options that are far from last resort.

@JanHudec You're right. But I made that point in reference to the statement made by the Malaysian defense minister- "If you're not going to shoot it down, what's the point of sending it (a fighter) up?" Hishammuddin asked. I'm not sure about the standard response of Malaysian defense forces as far as interception of hijacked aircraft is concerned; So, I'd answered it in light of the statement of defense minister, who as far as I know is responsible for handling this kind of stuff.


text:
Are there winglet modification regulations?
If an already existing fleet (737-800 and 900 without winglets) is thinking of a winglet modification, is that possible without regulations? Or what are the regulations?

Aircraft modifications in general are subject to airworthiness update. CAA (UK) // FAA (US).

Are you referring to the regulatory approval process that declares the plane (type) is airworthy with the addition of the winglet, or the physical installation on an existing plane of a previously approved winglet?

In the U.S., changing anything on the wing is considered to be a "Major Repair/Alteration" according to the FAA (FAR Part 43 - Appendix A)
To make those changes, this form - http://www.faa.gov/documentLibrary/media/Form/Form_337.pdf needs to be completed.
As you can see, it requires a certified mechanic to handle the work after which a person with Inspection Authorization would approve the aircraft for return to service.
A little extra reading - Who can perform different maintenance checks?.

It's more than checking the change has been done properly. You need to renew the type certificate if a winglet is added, which includes structural tests and flight testing before a mechanic can attach the winglet to the next plane of the same type. Legally, that is.


text:
Can ailerons be used for pitch change in the event of elevator failure?
On standard fixed-wing aircraft that have both ailerons and elevators, can ailerons function as elevators for pitching movement if the elevators fail? Technically it should be possible if both ailerons can rotate in the same direction simultaneously.
If so, what are the key differences and problems if the center of gravity of the aircraft was forward of the ailerons or behind the ailerons?
To my understanding, the farther back the control surface (which causes the pitching) is to the center of gravity, the bigger the pitching moment which results in a more stable configuration.

I suppose your question exclude elevons.

If the ailerons could be moved in the same way on both wings, the linkage between both is broken and they would float up near their maximum negative (trailing edge up) deflection angle. Even a hydraulic aileron booster would not help, since here still an interlink between both ailerons exists to keep actuation forces down. Only in a fly-by-wire aircraft with fully powered aileron actuators could the control system be programmed to allow symmetric deflection.
The effectivity of such a means of pitch control is very low, and only wing sweep can help to make it useable. Any pitch control input will change lift on the outer wing, and pitching up would mean a loss of lift and result in a plunging motion of the aircraft. If that happens on landing, when the pilot uses to pull the stick to raise the nose gradually, the resulting ground contact will be rather early and bumpy. Pilots of flying wings know this; they are very careful with their pitch control during a flare.
When an ASW-20 glider had crashed a couple of years ago because the pilot had forgotten to connect the elevator linkage, Gerhard Waibel flew to the glider club and demonstrated how to fly the ASW-20 with flaps for pitch control alone. The downside is a much reduced speed range and a high landing speed, because you need to reduce camber in order to pitch up, but it works. Since the flap span is higher than the aileron span, I would strongly recommend to rely on the flaps for pitch control when your elevator stops working if flaps are installed. They also do not need any modification to work as pitch controls since they are rigged to move symmetrically.
If the engines are mounted low or high, their thrust can also be used for pitch control. This was used on several occasions to bring an airliner down after all hydraulic circuits had failed.

EDIT:
Mike Dunlavey insists I should mention flaperons. He is right, they are possible with mechanical linkage only, but you will find them only on wings which have flaps anyway. All modern gliders with flaps will also move the ailerons in sync with the flaps.
But they are the worst choice for pitch control. For one, they are on the part of the wing with the smallest chord. Their lift change will go with the smallest pitch moment change of all controls except the rudder, so it would be much better to use the flaps for pitch control. That the ailerons do move with the flaps will have little effect. Besides, well designed flaperons will have less deflection change for a given flap change so the spanwise lift distribution will stay close to the optimum. This will make them even less effective than the flaps.
I choose not to mention them to make the answer concise. But I'm afraid short answers are not appreciated anymore.

Maybe I'm wrong, but I think your first sentence isn't completely correct. "Drooping ailerons" are not so common in non-fbw aircraft but the symmetrical/asymmetrical movement can be achieved with only mechanical links (I've seen it in a Lego model :) ). For instance this DHC-2 has both the ailerons deflected downward to provide additional lift. ;)

Ever heard of flaperons?

@MarcoSanfilippo I doesn't look like the ailerons are deflected much, if at all in that photo. Note that the neutral position of ailerons is almost always somewhat down because they're installed on the trailing edge of a wing, which points downwards to generate lift.

@MikeDunlavey Flaperons are an example of the fly-by-wire exception that he mentioned.

@reirab: No they're not. Take a look at that link, in particular the kit planes that use flaperons. It's just a matter of using aggregate-motion linkage from the control stick and flap lever.

@MikeDunlavey: Please see the edited answer. I know what flaperons are, but they are really bad for pitch control, therefore I did not mention them. Better use flaps!

I can't find a reference (maybe  you know of it) but I remember hearing about research that was being done on the Airbus to allow it to compensate for disabled flight controls using what was left.  Not sure how successful it ever was though.

I actually prefer the answer without flaperons since the original questions specifically asked about ailerons (only)!

@Lnafziger: Not sure about Airbus, but I know of work at MIT maybe 25 years ago where an autopilot software was developed which would randomly try small deflections and measure the reaction of the aircraft. If something failed, this allowed it to reconfigure the control laws quickly so almost any failure could be compensated. The researcher joked they should fly a UAV with that software and hand the Air Force generals shotguns, so they could damage the thing themselves and see how well it would cope. I think the modern F-16s use something similar.

The EMB-145 (and others in the family) have each aileron connected to one pilots yoke and an interconnect between the yokes to give both pilots control over both ailerons.  There is a cable to pull to disconnect the linkage (for jammed controls) and this lets each pilot independently control the ailerons on their side of the airplane.  You could use this with concerted motion to deflect the ailerons the same way on both sides to affect a pitching moment (the pilots would bank opposite directions from each other).

@PeterKämpf: Yes, I'm sure flaperons are really poor for pitch control, just as flaps would be, and if there was a way to hook the ailerons together so they could both be lowered, they would be flaperons. I'm pretty sure they have some effect, because typically when you lower the flaps before landing there is a nose-up effect that you have to compensate for by shoving the yoke a bit, before the extra drag brings the speed down. BTW, don't take anything I said as a criticism. I think it's great that people can discuss stuff like this.

I am a 100-hour pilot, so I know the basics.
Every civilian airplane requires decalage, which is an up-turning tendency.
Then if the plane is properly loaded, the center of gravity is forward of the center of lift. If there were no gravity, the plane would simply travel in a circular loop upwards.
The weight of the nose is what prevents that.
Why? For speed stability.
Both lift and the up-turning tendency are proportional to speed squared.
So if they go slower, the nose wins, carrying them down, which makes them go faster.
If they go faster, the wings win, carrying them up, which makes them go slower.
So, if the elevators become frozen, and you want to nose up, just give it the gas and go faster.
Either that or lower the flaps, to get more lift.
Or you could move some weight to the rear.

EDIT: This image is to show how to make a flaperon with purely mechanical linkage:

I don't think that's quite what would happen without gravity. Since gravity is what holds the atmosphere in place, it would be gone and wings and control surfaces will not to work very well in vacuum. :) On the other hand, there would be no drag, so fuel efficiency would be quite good, but with caveat that you need rocket engines instead of air-breathing engines.

@reirab: Use your imagination :) Did you ever read Arthur C. Clarke "Rendevous with Rama"? Large cylinder in space, full of air. Or do it under water, with neutral bouyancy. Or just turn the plane on its side, with a wire supporting its weight.


text:
Why Not Just Replace All the Fan Blades?
It looks like operators will have to remove all their P&W powered B777s from service until they have checked the engines.  Since the problem seems to be fatigue (which is a function of time) in a front fan blade, why not just replace all the blades in the front fan while you have it in maintenance?  What would be the cost of that compared to an inspection?

The cost would be significant. Those blades are usually inspected one-by-one at one of the checks, and any failing blades are replaced. Replacing an entire fleet of blades would be huge, especially since you need to disassemble them anyway.

How do you expect that replacing the whole engine fan is less expensive than an inspection?

It would probably take P&W a really long time to produce enough blades to replace every one in service on every engine on every 777 in the world. They're not cheap to produce, and it would be an immense expense to have thousands of them sitting unused in a warehouse, expecting (hoping) to never need most of them, as a "just in case" contingency.

I didn't mean to imply I thought replacing would be cheaper than inspection, I was thinking more along the lines of "the blades already have thousands of hours on them, even those that test ok may be getting near the end of their life, why not replace them all now then you won't have to worry about them for a long time."

"why not replace them all now then you won't have to worry about them for a long time" ? Well, just because they may have 1000's hours MTTF (mean time to failure), that's not a point in time; it's a distribution for the Failure rate. That's why everything gets inspected on regular schedules and after unexpected events. If you replaced them all at 80% MTTF, you'd be discarding good parts and still have failures. Discovering imminent failure by inspection way cheaper than by observation.

@Ron Ralph and Ian.  I agree with all three of you.  In hindsight it was not a very good question.